1998 Discover Technology Awards: Robotics

Wednesday, July 01, 1998

As head of the Mobile Robotics Lab at the University of Michigan, Johann Borenstein helps robots get around, and none of them can see a thing. "It's always been obvious," he says, "that the technology we have here could be useful to a blind person." A few years ago, Borenstein took a sonar device that helped one of his robots avoid obstacles and adapted it for humans. He translated the sonar's ultrasonic echoes into audible tones and fed them to stereo headphones. It didn't work. Blind users trying to interpret those cues quickly grew frustrated. Apparently getting a machine to detect obstacles is no big deal, but having it give directions to a human is. Whether you can see or not, you want something as intuitive as a tug on a leash.

From here, building the device was relatively simple. A graduate student mounted a sonar device to a pair of wheels, like an upright vacuum cleaner, that would take evasive turns, left or right, steering you around an obstacle, and then continue in the original direction. Borenstein never intended to reinvent the Seeing Eye dog, but that is exactly where the logic of the problem led him. So how does his eight-pound GuideCane stack up against its canine competition? "It's much less expensive than a good guide dog," about $4,000, he estimates, versus $14,000 for a dog. And his machine doesn't need to be fed or relieve itself. "Many people who are blind," he adds, "find it difficult to take care of a dog. But of course, GuideCane gives no companionship."

Borenstein demonstrated his GuideCane in August 1997, but it still needs tweaking: it has a habit of deviating from sidewalks and cutting across lawns. And it would be better, sometimes, not to avoid an obstacle, such as a wall that happens to have a door. If Borenstein also succeeds in including global positioning satellite navigation, you could simply say, "Go to the supermarket on Main Street," and GuideCane would escort you there.

For the past several years, people strolling around the Carnegie Mellon campus have delighted in watching a hubcap-size wheel skip across the quad. Nothing seems to stop it. Downhill or up, the little wheel keeps going. It hurdles bumps, swerves around obstacles (usually), and runs into things, bouncing off harmlessly (usually). Even when it falls on its side, it manages to pick itself up: it gyrates slowly and wobbles around on its rim, rising higher and higher until it's upright again, like a coin balanced on edge. Then it tilts, turns, and scoots away. This frisky wheel is, of course, a radio-controlled robot. A four-pound gyroscope concealed inside spins at 12,000 rpm and holds the wheel upright, whether it's rolling or not. Two internal motors drive it uphill and tilt the gyro to make the wheel turn, or even right itself after falling.

This happens to be a serious rover, but where did the idea come from? "When I was a teenager I worked in a gas station," says Benjamin Brown, Gyrover's inventor. "I rolled tires outside and was impressed that they didn't fall over--there was this inherent stability." Brown continued similar recreations as a mechanical engineer at Carnegie Mellon's Robotics Institute, going so far as to build a gyroscopically stabilized bicycle. Then the Japanese construction firm Shimizu asked him to come up with a new concept for lunar exploration. The jeeplike rover driven on the moon by Apollo astronauts seemed vulnerable to tipping; in such low gravity the wheels bounced crazily over bumps and ruts, even at slow speeds. What could be simpler and better, Brown thought, than a robot shaped like a tire, a unicycle stabilized by a gyroscope? The faster it went, the more stable it would be.

Brown had the first Gyrover, a steel bowl with a gyro and controls from a model airplane, running in two months. The second version, he says, "had a lot more engineering"--a fat fabric tire, the gyro enclosed in a vacuum. The latest version, which contains a computer for autonomous control, was completed in April, though Brown continues to tinker with the controls. On the moon, he says, a 30-foot inflatable model "would just roll over large obstacles." With cameras looking out the sides and radar scanning the ground, it would be ideal, he thinks, for mapping and surveying large areas. A more conventional robot could creep along behind, for claws-on exploration or collecting samples. "If you try to make Gyrover an all-purpose robot," Brown says, "sort of with arms sticking out, you lose the basic beauty of the design."

In July of last year the Sojourner rover touched wheels on Mars. For three months, with considerable effort and ingenuity, Earthbound engineers guided the little 24-pound Sojourner on a nail-biting journey, at times pushing 1/50 mph, that covered all of 334 feet. Three weeks earlier, on June 15, a 1,600-pound robot called Nomad, designed for planetary missions, set off across the Atacama Desert in Chile. Nomad cruised more than 125 miles in 45 days over equally challenging terrain, a record for telerobotics. Yet this speedy behemoth, standing shoulder high with four-wheel drive and four-wheel steering, proved ridiculously easy to operate. Children sitting 5,000 miles away at the Carnegie Science Center in Pittsburgh did much of the driving. On two different days, viewers watching public television steered Nomad by pushing buttons on their telephones.

A telerobot isn't just radio controlled, like a toy. It receives orders from two sources: a built-in computer with programs like obstacle avoidance and a human backseat driver. "It's actually more challenging to have telecontrol than an autonomous robot," says William "Red" Whittaker, a robotics engineer at Carnegie Mellon. Whittaker's team achieved the compromise between willful human and smart machine with two levels of telecontrol: a safeguard system that overrides remote commands to avoid immediate hazards (good for the moon), and a semiautonomous mode that lets the remote operator pick targets, which Nomad figures out how to reach (good for Mars, where steering signals from Earth take ten or more minutes to arrive).

To help its human operator see, Nomad contains a panospheric camera, focused straight up on a half-sphere mirror atop the robot. This gives a full 360-degree view with no need to pan and no moving parts. A mechanically aimed antenna beams these visual data at high-enough rates for a remote receiver to correct the mirror's distortions and project the ever-changing view on a 360-degree screen, immersing controllers in the alien landscape. "It's so distant from that prior paradigm of waiting for single snapshots," Whittaker says. Whereas it took months to get 550 photos back from Sojourner, he says, Nomad could have taken as many in a few minutes.

Nomad's next scheduled trek, a breezy jaunt over Antarctica's glaciers in November, will allow telegeologists to hunt for meteorites from comfortable digs a hemisphere away. After that, Whittaker expects downsized descendants of Nomad to do hard labor on the moon--prospect for water, say, or bulldoze a base camp--and even on Mars and beyond. "We've gotten to a sense of impossibility," he contends, "that says smaller is better, and that has led to a mania for mini- and micro-rovers. But check out Viking [a 1,300-pound craft that landed on Mars two decades before Sojourner]. That was no lightweight." And NASA sent two.

When Randy Beer showed Roger Quinn his doctoral research in the late 1980s, "I was impressed," Quinn says. Beer, a computer scientist, was looking at insects as a source of ideas for robots. Cockroaches, for instance, are among the fastest land animals in the world if you consider body lengths traveled per unit time. "Anyone can appreciate how hard it is to step on them," Quinn points out. Beer's work inspired an entire program in biorobotics at Case Western Reserve University, which Quinn, a mechanical engineer, is now part of.

Legged robots had long been viewed as alternatives to wheeled vehicles in rough terrain: they can raise themselves higher over obstacles, scale steeper slopes, probe gingerly ahead before committing full weight. With these advantages, they might lead search-and-rescue missions, explore alien worlds, lay underwater cable, or remove mines. But walking is no simple task; roboticists have devoted years to figuring it out. Quinn's group started by analyzing videos of bugs on treadmills, extracting sticklike models of their biomechanics. "Posture, body angles, joint movement and leg movement came right from the biology," Quinn says. "That was beautiful." Then they developed control algorithms. "The secret," Quinn says, "is to avoid total programming," which leads to unadaptive, "brittle" gaits. Instead, they enshrined a few simple reflexes: when blocked, try elevating the leg (step up); when encountering a hole, "search" it (probe forward, deeper, and step over and down); or if no other dumb reflex gains a solid foothold, then "change direction." With no more intelligence than that, away the little devils scamper. "You can't dictate which leg it lifts and how much weight should go on each foot--it has to figure this stuff out," Quinn says.

The nearly completed roach in progress, Robot III, is awaiting electronic controls. When finished, it should look and act remarkably like the real thing, although, at two-and-a-half feet, it's 17 times longer and weighs 30 pounds. Its large, three-jointed rear legs, powered by pneumatic pistons, push it quickly forward; smaller front legs, with five joints, feel their way along. Like earlier models, this critter sways when disturbed, adjusts its posture, does push-ups with ease, and carries a payload as heavy as itself. The goal, however, isn't to build roach replicas but to make practical, cockroachlike robots that do useful things. Right now, though, they are too complex to manufacture en masse. "When we've got it right," Quinn predicts, "it usually ends up fairly simple."

Minefield Fodder K2T's Walking Machine Innovator: Eric Hoffman

Removing live mines is dangerous work anywhere, and it's especially difficult underwater. It would be nice, then, to dispatch robots, rather than humans, to clear harbors or beachheads. But that raises another problem. Wheeled and tracked vehicles are limited by terrain, but mines are not. That's why Eric Hoffman and his colleagues at K2T, a robotics company in Duquesne, Pennsylvania, decided to develop a robot with legs.

Compared with wheels, legs are a challenge for engineers. "The technology is really new," Hoffman says, "and very few people have tried it." The K2T engineers settled on an eight-legged, crablike design. To control those legs, they turned to research at Case Western Reserve University on giving robots autonomous, insectlike responses to varying terrain. Hoffman's group simplified the algorithms for an eight-legged gait, so that four at a time moved in concert. Their Walking Machine, though less nimble than the state of the art, nevertheless scuttled over obstacles. But the mine-detection problem remained: their guiding word, says Hoffman, had to be "expendable." To hold production costs to a few thousand dollars per machine, his team used off-the-shelf electronics and molded plastic for mechanical parts. The current version is three by three feet, weighs 36 pounds, and runs four hours on batteries. Last October this machine demonstrated its munitions-removing prowess in the halls of Congress.

Still, the company has no plans to continue development. Cheap fabrication isn't the problem, Hoffman says. And there are certainly plenty of land mines--110 million by UN estimates. But to date, no one has approached K2T with funds to invest in development.